Scabies is a common skin problem caused by tiny mites. The mites burrow into the skin, and cause small itchy bumps and blisters. Scabies mites have eight legs and a round body and are pretty hard to see. When they're fully grown, each mite is no bigger than the size of the point of a pin. But for such small critters, they sure can make you uncomfortable! The doctor gives kids who have scabies a cream to help stop the itching.